Centrifugal governor



Sept. 28, 1937. s. R. TOWN 2,094,196

CENTRIFUGAL GOVERNOR FilOd All. 7, 1934 Z Sheets-Sheet 1 Flgl A FIQZ. A m i m' m FIGS 22 as l7j9 I 1? 14 12 u Z2 u d g m 16 d I 1 %17b I INVENTOR.

l Gnome: 2.13m:

ATTORNEY.

Sept. 28, 1937.

MOMENT- KILOGQAM-CENTIMETERS s. R. TOWN 2,094,196

CENTRIFUGAL GOVERNOR Filed Aug. 7, 1934 2 Sheets-Sheet 2 Fig.3

. 0 +20 +30 9 DEGREES INVENTOR. Gnome I2. Towu ATTORNEY.

4 Patented Sept. 28, 1937 UNITED STATES PATENT OFFICE CEN'I'IIIFUGAL GOVlI-HOI Application August 7, 1934, Serial No. mm 14 Claims. (Cl. 234-15) My invention relates to centrifugal governors and more particularly to such governors of the gravity or force loaded type which are substantially neutral over an extended range of operation.

The centrifugal governor of my invention comprises a rotatable member including a pivotal support. One or more governor weights are pivoted on the support and cooperate with a control member or arm which controls or regulates the action of the governor or other controlled mechanism. The angle between the pivotal radius of the weight, that is, a radius from its pivotal axis to its center of gravity, and a radius of rota- .tion to the pivotal axis, for the normal position of the control member, is such that the governor is substantially neutral over a range of movements of the governor weights; that is, the rate of change of centrifugal moment of the weight with respect to its deflection about its pivotal axis is equal to the rate of change of the controlling moment with respect to governor deflection over a wide range; preferably, the rates of change are zero for the normal position of the governor weights.

Further, in accordance with my inventiomthe angle between the pivotal radius and the radius of rotation, and the ratio between the pivotal radius of the weight and the radius of rotation to the pivotal axis are such that the centrifugal moment of the weight about its pivotal axis varies as the cosine of the angle of pivotal deflection. More particularly, the radius of rotation is large compared with the pivotal radius and, by way of example, may be of the order of eight times the pivotal radius.

Further, in accordance with my invention, the 'control arm or member is a unitary structure with the weight and pivoted therewith about a common axis; it is subjected to a controlling force applied at a predetermined point, so that the moment of this force about the pivotal axis also varies as the cosine oi the angle of deflection of the governor weights.

For a better understanding of my invention, together with other and further features thereof, reference is had to the following description taken in connection with the accompanying drawings andits scope will be pointed out in the ap- 50 pended claims.

In the drawings, Fig. l, to aid in the explanation of my invention, is a schematic diagram of/the essential elements of a centrifugal goverr jr;

Fig. 2 is a schematic diagram, of the essential elements of a different type of centrifugal governor, to aid in the explanation of my invention;

Fig. 3 illustrates characteristic curves of moment plotted against degrees of governor deflection as abscissae of governors of the prior art and of governors constructed in accordance with my invention;

Fig. 4 is an elevation, partly in section, of a centrifugal governor embodying my invention, as applied to a system for measuring fluid flow;

Fig. 5 is a plan view of the right half of the governor of Fig. 4 and a sectional plan view of the left half of that governor taken through the knife-edge pivot of the governor weight;

Fig. 6 is a detail of a knife edge bearing utilized in the governor of Figs. 4 and 5;

Fig. '7 illustrates the application of my invention to the governing of the speed of drive of an astronomical telescope. Referring to the drawings, my invention will be best understood by first referring to Fig. 2 wherein there is illustrated, schematically, a centrifugal governor of the double arm type, comprising masses m considere as concentrated at points, supported respective y upon arms a pivotally mounted about points 0 which rotate about the axis AA. The arms a, respectively, have secured thereto as unitary or integral elements, arms b which project from the respective pivots 0 toward the axis of rotation A-A. The controlling force or weight W, movable along the axis A-A, is applied at the points c' at distances 1 from the pivots o. The aforesaid double arm type of governor facilitates balancing, both statically and dynamically.

The angles between the respective arms a and b, which in effect comprise bell cranks, are represented by the angles o, while the deflections of the masses m and their connected arms from their normal position may be represented by angles 9. The lengths of arms a are represented by symbols s; the radial distances between the axis A--A and pivots o are represented by symbols p. In this case the moment arm of the controlling force W varies as cosine 8, and for a given constant controlling force the moment M; of this force also varies as cosine 0. On the other hand, the moment M. of the centrifugal force about each pivot o varies not only with the speed of rotation of the governor but also with the radius of each mas m about the axis AA, i. e. with the deflection of the governor.

In the case of centrifugal governors of the gravity type, as shown in Fig. 2, that is, governors subjected to a controlling force independent of the deflection of the governor weights. as contrasted with spring-loaded governors in which the loading force varies with the deflection of the weights and the spring, it is desirable that the force reacting against the controlling force, and due to the moment of the centrifugal force of the weights about their pivots, be a direct function only of the speed of the governor and independent of the deflection of the governor weights. When this is true, by controlling the driving means of the governor in accordance with its defiection, a predetermined relation may be established between the magnitude of the controlling force and the speed of the governor. Such an arrangement is useful in many mechanical systems, examples of which are described in detail hereinafter.

The above conditions are satisfied, obviously, only when the resultant Me of the centrifugal moments of the governor weights m about their pivots 0, is equal and opposite to the moment M of the controlling force, at any given speed, for all angles 6 of deflection of the governor weights. However, for the usual relationship of parts, the centrifugal moment of the governor is not constant for all deflections, but follows a predetermined curve. The moment of the applied force may also be made to follow a predetermined curve, for example, a cosine curve; and, by a proper proportioning of the parts in accordance with my invention, the curve of'the centrifugal moment Me, with respect to deflection of the governor weights m, may be made to approximate the curve of the moment M of the controlling force, so that the centrifugal moment and the moment of the controlling force are substantially equal for all deflections of the governor at a given speed and are independent of the deflection of the governor weights, which imparts to the governor substantially neutral characteristics; that is, characteristics such that the governor remains in equilibrium through a range of movements of its arms a. In other words, for a constant governor speed, the variation in the resultant Me, which varies with changes in the centrifugal force developed by the weights m and changes in the lengths of their respective moment arms occasioned by movement of the weights m through a substantial range, is compensated for by a corresponding variation in the opposing moment M developed by the controlling force W. The moment of the controlling force is made up of two components, the magnitude of the controlling force W and its lever arm I cos 9. By applying the force vertically at predetermined points c of normally horizontal control arms 11, the lever arms vary as the cosine of the angle 6 of deflection from normal position and the moment of this force, M also varies in the same manner. Accordingly the gravity biasing moment M may be expressed by the equation of parts, the moment or lever arms of the centrifugal weights may be made to vary at such rates with respect to the variations in the centrifugal respect to 0, i. e. the cosine curve.

force with variations in deflections of the weights that the rate of variation of their product Me is zero for the normal position of the control arm, while this product varies approximately as the cosine of the angle of deflection therefrom. The

normal position of the control arm is the one where the centrifugal moment is a maximum for a given speed of rotation. By causing the moment of the applied force to vary also as the cosine of the angle 6 of deflection, as described above, the required applied force i. e. that required to balance the centrifugal force with varying governor speeds will vary precisely with the square of the speed of the governor over an extensive range of deflection, thereby substantially increasing the accuracy of the governor.

In order to secure neutral characteristics two considerations become important: First, the curves of the centrifugal moment MC and the controlling moment Mg with respect to 9 must be tangent at the normal position of the governor, which usually corresponds to 6=zero; and further the curve of the centrifugal moment Me with respect to 9 must coincide with or approximate the curve of the controlling moment M with If both of these conditions are satisfied, the axial force opposing W will be dependent only on speed, and will be independent of the deflection 9 of the governor.

The first of the above considerations is satisfied if the curves of Me and M with respect to 6 are tangent or have the same slopefor the normal position of the governor, that is for 9:0. From an inspection of Fig. 2 it is clear that:

where a is the angular velocity of the governor in radians per second and g is the acceleration of gravity; and

Since the slope of Me at 6:0 is zero, it is evident that, as the radius of rotation of the mass increases, its lever arm must decrease; therefore 4 must have a value between and degrees; that is the cosine is negative and: r n/F4 85 T (7) If the relationship of Equation ('7) is satisfied, the governor will be neutral at 9:0 but not necessarily for any other position. In order to extend the range of neutrality, it is necessary that the curve Me shouldcoincide with or approximate the curve M over the desired range of operation. Equating (1) and (2) to fulfill this condition:

Since the governor is neutral at 6:0 as determined above, from (8) is obtained:

Substituting (9) in (8) and simplifying gives:

2p cos qt sin 9 sin 2(4 +6)sin 2. cos 9 (10) It can be shown that this last expression is satisfled only when :90 and the ratio p/s is inflnite.

However, the above relationship may be approximated and the governor made substantially neutral over a considerable range by making the ratio p/s large. For example, I have found that. with a ratio p/s of 8 or greater, the deviation of Mn from M is less than 0.1% over a range of deflection of the governor of 35. In' the preferred embodiment of my invention I utilize the ratio 9/3 of approximately 8.

In Fig. '3 are shown curves representing the conditions discussed above for one particular speed.- Since in accordance with my invention the moments Me and M; vary equally in sense and in magnitude for different deflections of the weights m, it is convenient to plot moments as ordinates against the deflection of the weights m, measured in degrees of deflection of the weights from their normal positions as abscissae. (The normal positions of the respective weights m are those positions which produce a maximum resultant moment Me for any given speed.)

The maximum ordinate of curve B, representing the moment M of the controlling force, occurs at a value of 6:0. If the weights m be deflected in either direction (without change in speed oi arms b) from the neutral positions, shown in Fig. 2, the controlling moment M; decreases in accordance with decrease in the value of cos 9.

In case the governor is proportioned in accordance with Equation ('1) its characteristics are represented by curve D of Fig. 3 which is tangent to curve B for the normal podtion of the governor, at which 6:0, but is much more peaked, i. e. diverges rapidly from curve B on both sides of the normal governor position. Such a governor is neutral only in the immediate neighborhood of 9:0. If such a' governor is utilized to control the speed of the motor driv ing the governor, an error will be introduced into the speed regulation for those positions of the goverrbor outside of the aforesaid neighborhood 0! 9:

Curve E represents the centrifugal moment of an actual centrifugal governor constructed in accordance with my invention and proportioned as determined by the above equations and constructed as described hereinafter; specifically with a ratio p/s:8. It is seen that, on the left hand side of Fig. 3, the curve E is substantially coincident with curve B. Over a range of from to +10 the maximum deviation between curves B and E is less than 0.1%. While the angle 6 has been considered as the deflection of the governor from its normal position, in this speciflc example the position of the governor corresponding to the midpoint in the range of minimum error is'prei'erably utilized as the normal position, in the above case at 6=7%, to pro.- vide an equal range on opposite sides of normal with the same minimum error.

The curve A represents the application of a' constant controlling moment M to a governor of the type shown in Fig. 1 wherein the weight W is applied to a single arm b by means of a roller c or the like. Since the weight acts along the axis A-A on the roller 0, the distance 11 between that axis and the pivot 0 remains constant irrespective of deflection of the weight 1n. As in the case of Fig. 2, the arm'a bears a fixed angular relationship with respect to the arm b indicated by the angle 15. By proportioning the parts in accordance --with Equation Number (7) and with a ratio of p to s of the order of 8,the curve E represents the centrifugal moment Me- It is seen also that curve E closely approximates curve A in the neighborhood of 9:0; within a range of :2 the -deviation between curves A and E does not exceed 0.1%. That is, even with a control mechanism of the type illustrated in Fig. 1, in which the controlling moment M; is constant, approximate neutrality may be secured by proportioning the governor in accordance with the foregoing formulae. v

Contrasted with the foregoing is curve C rep resenting the centrifugal moment Me of a governor when not constructed in accordance with my invention. It ls seen that Me and Mg are equal only at the two points W and X.

In the foregoing discussion it was assumed that the centrifugal weights m were point masses and the masses of the bell cranks were disregarded. However, I have determined that a mass of uniform density and thickness with a cross-section having axes of symmetry parallel to the axis of rotation and a radius of rotation of the mass, and disposed with its axis normal to both of these directions, is the equivalent of a point mass concentrated at its center of gravity. Best known examples of such masses are solids of revolution such as spheres, cylinders and the like, whose centers of gravity lie on their axes of revolution and I utilize in the preferred embodiment of my invention masses in the form of circular cylinders.

The mechanical structure and physical characteristics of the governor embodying my invention are best shown in Figs. 4 and 5 of the drawings which illustrate an embodiment of my improved governor in a system for measuring fluid flow. Referring more particularly to Figures 4 and 5, there is provided a rotatable plate or support "from which project two pairs of upstanding posts or arms i I. Between each pair of posts II is supported a cylindrical bearing block I! mounted in recesses Ha of the posts II and provided with a V-notch bearing recess II. The bearing blocks I! are retained in position by means of set screws II and suitable lock-nuts Ii.

Since the centrifugal moment of the governor depends in part upon the mass of the governor weights, and since, for approximate neutrality, the pivotal radius is small for a satisfactory radiusof rotation, the problem arises of procuring a governor weight or considerable mass mounted with a short pivotal radius. If mounted in the conventional manner, the radius of the solid of revolution must be less than the pivotal radius, which" would require an excessive longitudinal dimension for a reasonable mass. I have solved this problem, however, by utilizing governor weights II in the form of cylindrical disks of considerable radius and pivoted, respectively. within their peripheries'but eccentrically: thus consid-. erably reducing, for a given mass, their longitudinal dimension. These disks II are supported from the bearing blocks i2 and are provided with eccentric bores or openings Ila considerably larger stantially on-their-geometric axes;

than rbearingablocks ii. to Provide limited freedom of movement of the weights -I8 about the bearings I2. Secured within the disks I6 are the knife edges I1 shown in detail in Fig.- 6. These knife edges rest in the V-not'ch bearings I3, I3

of. the bearing blocks I2 and serve pivotally and eccentricallyto support the disks IS. The knifeedges I1 are-provided with apertures oropenings The controlling force W, referred toin connec tion withFig. 2 and here developed by a tilting manometer 34, is applied to thegovernor by means of a rod I9 secured to the inner plate 20a of a ball, radial, and/or thrust bearing 20, the outer plate 20b of which supports a bearing block-2|. Each of the governor disks I6-is provided-with a pair of inwardly extending control arms 22, corresponding to arms'b of Fig. 2, between'the ends of each pair of which is pivotally supported a block'23 bearing upon the block 2| and eflective to transmit as a crank arm the centrifugal force developed by the governor disks I6 to' the control rod I9. The arms 22are con nectedcto the'disli-weights I6in a manner such that a line, representing the radius of weight It and corresponding, to left-hand arm m of Fig. 2, extending from the knife-edge pivot (corresponding to pivot o of Fig. 2) to the center of gravity of the disk .IG lies at 'an angle 9 with respect to a line extending fromthe knife-edge pivot to the point on arm 22 at which the bias is applied from the manometer 34." The cosine-of the angle .9 conforms to the requirements of Equation: (7).: The distance 1 is of course measured from the knife-edge pivot to the axis of rotation, ,or to the axis of rod I9 which coincides with the axis of rotation; The lowerend'of'the rod I3, which is axially movable but non-rotatable, is journalled in a bearing supported in the base Iiltomaim tain proper alignment.. This end of the rod I9 may move in a recess 25a'of a vertical support 23 upon which, the base It is supported and secured by, means of suitable set screws 2i....- .The

%:ased within a shell or housing 23.

support "25 may be rotated .by any suitable-type of 'motor such as an electric motor 21. The governor mechanism. per se, is preferably en?- In the system illustrated the" governor is adapted to measure the fluid flow in a conduit 3II--provided with a device for producing-a differential pressure representative of the fluid flow through the conduit. suchas-an orifice 3|. The pressures on opposite sides of the orifice mare transmitted through the pipes 32 and." to the'arms 34a and 34b of the tilting manometer 34 secured to a frame 35*mounted ona knife edge and bearing block 36. Suitable shut-ofl and equalizing valves 31 are included in the pipes 32v and 33 for calibrating the manometer and-placing it in and out. of service, as well understood by those skilled in the art; also condensers 33 may be included in the lines 32 and '33. I

The frame 35 actue es contacts 39 connected to control or regulate, in any well known manner, the speed of the motor 21. For example. the

contacts 39 may be included inthe'circuit- '10: the motor 21, which may be energized from any contacts 39 are open, as illustrated, that the motor has been previously energized and is coasting. and

thatfluidis flowing in the conduit 30. Flow of fluid in -the conduit 30 produces a differential pressure across the orifice 3I which is impressed upon the arms of the tilting manometer 34 and displaces the liquid, preferably mercury, from one arm, as 34b into the other arm, as 34a, causing an unbalance and tilting of the manometer and frame 35. The unbalance force, due to the differ ence in the weights of the columns of liquids in the two arms of the manometer 34, produces'an upward pull on the rod I9 which pull or force is transmitted to the control arms22 of the centrif-- ugal weights or disks I6. In case the speed of the motor 21 is insuflicient to produce, by means of the disks I6 an adequate force on the bearing block 2I to balance the control force exerted by the rod I9, the rod I9 will move upwardly and the frame 35 will be eifective to close the contacts 39, energizing the motor circuit and increasing the speed of the motor and the governor. This increasezin speed will continue until the moment of the centrifugal force developed by the weights I6 predominates over the moment of the control force for'the existing fluid flow through the conduiti3ll, when the control rod I9 will be moved downwardly breaking the circuit of the motor 21*at the contacts 39 and allowing. the motor to slowdown. The making and'breaking of, the contacts 39 is relatively rapid so that the deviation of the speed of the motor 21 from its mean value is insubstantial or negligible, this mean speed being determined by the balancing of the moment of the centrifugal force of the weights I8 and that of the control force exerted by the tilting manometer. It is well-understood in the art that the difleren tial pressure developed across an obstruction such as the oriflce 3i is proportional to the square of the rate. of flower fluid passing the orifice. It is also-well known that the centrifugal force developed by a rotating mass is proportional to the square of the speed of rotation. -IBy balancing these two forces, each proportional to the square of the primary condition. a linear relation is established between the rateof flow-of fluid in the conduit 33 and the speed of rotation of the motor 21 so thatthe speed of rotation of the motor 21 is a direct and linear measure of the flow of fluid in the conduit III; and moreover the number ofrevolutions of the motor 21 is a direct and linear measure of the total quantity of fluid passing the orifice 3|. By attaching a counter 42 and a tachometer l4 tothe motor 21, both the rateof.

flow and-the total flow may be continuously indicated and/or recorded, as desired. Similarly,

by actuating contacts 43 by the counter 42, the revolutions of the motor 21 may be transmitted to am remotepoint at which either the speed of rotation or the total number of revolutions or both may be indicated or recorded.

' In'order that the above described system may the speed'of the motor 21 be accuratelygoverned or controlled to correspond closely to the magnitude of the controlling force.

applied to rod I! is a function of speed only, if the governor is proportioned in accordance with the formulae derived above. In all other cases the force will be dependent also upon a factor including the deflection of the governor disks from their normal position, so that for a change in manometer unbalance, due to a change in the rate of flow, the required change in the speed of the governor to procure rebalanoe is not a linear function'of the aforesaid chansed rate of flow.

However, by proportioning the several governor parts in accordance with the formulae derived above, the force varies as the square of the speed of rotation; it iscompletely independent of the deflection of the governor weights throughout a considerable range on either side of the normal position of the-governor; the speed of the governor, varied by changes in the controlling force W, becomes an accurate measure of the rate of flow of fluid through pipe or conduit 30. For example, with the parts in the position shown in Fig. 4, a large increase in rate of flow through the conduit ll would cause the fluid to rise in manometer arm a; the resulting increase in the unbalanced force acts to move rod is upwardly and to deflect or rotate the respective disks it. Thus the deflection of the disks I 6 from their neutral position may be great. The switch 3!, closed as soon as the weight or disks l6 move a predetermined amount, energizes the motor 21. The increasing speed of rotation increases the centrifugal moment Me which, as soon as it exceeds the controlling moment Mg, returns weights or disks It, the rod I 9 and the switch 39 toward their original positions. As before, the switch 39 opens its contacts, the speed decreases, the weights deflect to close the switch and the action is repeated accurately to maintain the governor speed in its proportional or linear relation to the rate of flow. As stated above, the centrifugal moment Me and the controlling moment M. (curves E and B Fig. 3) vary in the same sense and to the same extent with deflection of the disks It so that the speed regulation is independent of variables introduced because of change in the position of the disks or their associated arms; in other words, the governor is neutral over a wide range of deflections. In this connection it is to be pointed out that it is not any speciflc dimension of the governor, such as the radius of rotation of the governor weights or their pivotal radius, but the proportionlng of the several constants of the governor in accordance with the above equations, which imparts to the governor its neutral characteristics. In general the governor weights are free to deflect throughout their wide range or angle of deflection in response to the predominant one of the centrifugal or gravity biasing moments until the other moment predominates. These moments, as already shown, may be expressed approximately by the equations Mc=Fek C08 9 Mg=WK C08 9 where Fe is the centrifugal force; is, K are constants; W is the gravity biasing force and 6 as before is the angle of deflection of the governor weights from a position where the centrifugal moment Me and the gravity biasing moment M for a given speedhave their 7 4 As pointed out above, the force developed by the weights It and unavailable.

It is therefore clear that the deflection of the governor weights throughout the wide angle of at least thirty-flve degrees is dependent only upon the predominate one of the centrifugal or gravity biasing forces. The deflection of the governor weights is not affected by the change in the moment arms ted with either of the aforesaid forces Fe and W since, as shown by curves B and E of Fig. 3 for a given speed, the moments Me and M change in the same sense and by equal amounts throughout the neutral range of the governor or for all positions of the governor weights within the wide angle.

In Fig. 7 there is illustrated an application of my invention to the driving at constant speed of an astronomical telescope. Such an application is particularly advantageous in remote observatories where sources of alternating current.

of accurately controlled frequency are usually In this instance an astronomical telescope 5. is supported in a yoke 5| pivotally mounted on a pedestal 52. Telescope 5B is attached to a shaft 53 by which it is driven, while the shaft 53 is rotated by a governor controlled motor 21 through suitable gearing 54, a flexible shaft a, gear box and gearing 56. In this instance the constant controlling force applied to the control rod I! of the governor G is supplied by a weight 51, adjustably secured to a beams 58 fulcrumed on a knife edge 59. As in the arrangement of Fig. 4 the beam 58 controls contacts I! in the energizing circuit ll of the motor 21. The operation of the apparatus of Fig. 7 is in all respects similar to that of Fig. 4 with the exception that the controlling force impressed by the weight 51 is constant in magnitude, so

that the speed of the governor G and the motor 21 is maintained at a constant value to balance the centrifugal force of the governor against the controlling force. Because of the extremely high accuracy of the governing apparatus G when constructed in accordance withmy invention, the telescope 5| may be maintained in accurate alignment on a particular point or region under obmrvation.

While I have described what I at present consider the preferred embodiment of my invention, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit of my invention, and I therefore aim, in the appended claims, to cover all such changes and modiflcationsasfallwithinthetruespiritandscope of my invention.

What I claim is:

1. A centrifugal governor having neutral characteristics for a wide range of governor-weight positions comprising arotatable member including a pivotal support having its pivotal axis displaced from the axis of rotation by a distance p, a deflecting weight pivoted on said support with a pivotal radius s not greater than oneeighth p and extending from the center of gravity of said weight to said pivotal axis, gravity biasing means including a member movable by deflection of said weight, and a control arm extending at an angle 0 from said weight, one end of said arm being rigidly secured to said weight and the opposite end of which receives at a point, the bias of said gravity biasing means, said angle 0 being measured between a line connecting said pivotal axis and the center of gravity of said weight. and a line connecting said pivotal axis and said point on said arm, and said angle being determined by the relation P\/p cos rt- 48 2. The combination with a motor and means operable from one position to another for controlling the speed of rotation of said motor, of a governor having at least one deflecting weight driven by said motor, a supporting member including a pivotal support for said weight having its pivotal axis displaced from the axis of rotation by a distance p, said deflecting weight pivoted on said support with a pivotal radius s not greater than one-eighth p and extending from the center of gravity of said weight to said pivotal axis, and a control member rigidly secured to said weight at an angle 0 with respect to said radius s, said angle 0 being determined by the relation and means operable by deflection of said weight for actuating said control means.

3. A centrifugal governor comprising a rotatable member including a pivotal support displaced from the axis of rotation of said member, a weight pivoted on said support for deflection at a given radius from its pivotal axis through a large angle, a control arm having one end rigidly secured to said weight, gravity means for applying a biasing moment at a given point to the opposite end of said am, the magnitude of said moment varying as the cosine of the angle of deflection of said weight from a position where said moment is a maximum, the angle between the radius of said weight and a line connecting said pivotal axis and the point of application of said gravity biasing moment to said arm being so proportioned that the centrifugal moment of said weight about its pivotal axis varies approximately proportionally with the cosine of the angle of pivotal deflection of said weight through said large angle of deflection thereby to impart neutral characteristics to the governor for every deflection within said large angle.

4. A governor comprising a deflecting weight movable by centrifugal force about a pivotal axis in response to change of speed, a control arm operatively associated with said weight and movable therewith, means mounting said weight and said arm for rotation about a given axis the distance of said pivot from said axis of rotation being of the order of eight times the length of a line connecting the center of gravity of said weight and its pivotal axis, gravity operated biasing means for applying an opposing moment to said control arm which varies in accord with the cosine of the angle of pivotal deflection of said weight, and the angle between said arm and said connecting line being selected to produce, through a substantial range of deflections of said weight on opposite sides of a position of said weight at which the moments of centrifugal force and of said gravity biasing means are equal and have their maximum values, simultaneous variation of said centrifugal moment in the same sense and by amounts equal to those of said gravity biasing moment whereby for a given speed and-a given bias said weight is free to deflect throughout said range without disturbing the equality between said moments.

5. A centrifugal governor comprising a rotatable member including a pivotal support displaced from the axis of rotation of said member, a weight pivoted on said support for deflection at a given radius from its pivotal axis, a control arm having one end rigidly secured to said weight, gravity means for applying at a given point a biasing moment to the opposite end of said arm varying as the cosine of the angle of deflection of said weight from a position where said biasing moment is a maximum, the angle' between the radius of said weight and a line connecting said pivotal axis and the point of application of said gravity biasing moment to said arm being so proportioned that the centrifugal moment of said weight about its pivotal axis varies approximately proportionally with the cosine of the angle of pivotal deflection of said weight through a wide range of angles of deflection thereby to impart neutral characteristics to the governor over said wide range of said angles of deflection, and means movable in accordance with deflections of said 'weight for controlling the speed of rotation of said weight.

6. A governor comprising a deflecting weight having a pivotal radius s, means mounting said weight for rotation about an axis displaced from the pivot of said weight by a radius p, a control arm disposed in a fixed angular position with respect to said pivotal radius and deflecting with deflection of said weight, the angle between said pivotal radius s and said control arm being determined by the relation 5 and the ratio of p to s being at least 8, and gravity biasing means applied to said arm, the resulting moment varying as the cosine of the angle of deflection of said weight, thereby to impart neutral characteristics to the governor over a wide range of deflections of said weight.

7. A centrifugal governor having neutral characteristics throughout a wide range of deflections of the governor-weights comprising a rotatable member including a pivotal support, at least one deflecting weight comprising a solid of revolution pivoted on said support with the axis of revolution of the generatrix of the solid of revolution parallel to its pivotal axis, the radius of rotation p from the axis of rotation to said pivotal axis being of the order of eight times the pivotal radius s of said weight, a control arm rigidly secured at one end to said weight, said pivotal radius s being disposed at an angle from a line extending between the free end of said arm to said pivotal axis, the cosine of said angle having a value determined by the relation so that the centrifugal moment of the weight about its pivotal axis varies approximately proacteristics throughout a wide angle of deflection F or the governor-weights comprising a rotatable member including a pivotal support having its pivotal axis displaced from the axis of rotation bya distance p, at least one deflecting weight comprising a cylinder pivoted on said support withapivotalradiusanotgreaterthanoneeighth p, a control member rigidly secured to said weight at an angle with respect to said radius a such that the centrifugal moment Me of said weight is proportionalto the relation Fe cos 9 where Fe is the centrifugal force developed by said weight, and 9 is the pivotal deflection of said weight from a position where for a given speed Me is a maximum, means including a gravity biasing means for applying to said control member a controlling moment M; proportional to the relation W cos 6 where W is the force developed by said gravity biasing means.

7 9. A centrifugal governor comprising arotatable member including a pivotal support displaced from the axis of rotation of said member, a weight pivoted on said support for deflection at a given radius from its pivotal axis, a control arm having one end rigidly secured to said weight, gravity biasing means for applying at a given point on the opposite end of said am a gravity biasing moment which varies as the cosine of the angle of deflection of said weight, the ratio between the length of said radius and the distance of said pivotal axis from said axis of rotation, and the angle between the radius of said weight and a line connecting said pivotal axis and the point of application of said gravity bias to said arm being such that the centrifugal moment of said weight about its pivotal axis and said gravity biasing moment vary in the same sense and by equal amounts for all deflections of said weight within a twenty-flve-degree zone on one side, and a ten-degree zone on the other side,

' of the position of said control arm at which said moments for a given speed have their maximum values.

10. In a centrifugal governor, having a deflecting weight with a radius a extending from a pivotal axisandanarmdisposedinaflxedangular position with respect to said pivotal radius and deflecting with said weight, the combination with a control member operable by centrifugal force transmitted thereto by said arm, and the angle between said arm and said radius being such that over a wide range of deflections of said weight the centrifugal force applied to said control member is proportional only to the square of the speed of rotation of said weight and independent of the position of said weight within said wide range of deflections. 11. A centrifugal governor substantially neutral for an extended range of operation com'prising a rotatable member including a pivotal support having its pivotal axis displaced from the y axis of rotation by a distance 9. a weight pivoted on said support with a pivotal radius s, and a control member rigidly secured to said weight, the

angle 9 between the pivotal radius of said weight and said member being determined by the relation tral for an extended. range of operation comrising a rotatable member including a pivotal support having its pivotal axis displaced from the axis of rotation by a distance 9, a weight comprising a cylindrical disk pivoted on said support near its center but displaced therefrom by a distance s which is small relative to the distance p, a normally horizontal arm secured to said disk and projecting therefrom in a line intersecting its pivotal axis, the angle o between the pivotal radius of said weight and said control arm being expressed by the relation rim? and the ratio 9/: being such that the centrifugal moment Me of said weight about its pivotal axis is expressed approximately by the relation M=F it cos 6 where Fe is the centrifugal force, 9 is the pivotal deflection of said arm from a position where Me is a maximum and k is a constant, and control means for subjecting said arm to a controlling force at a predetermined point near its outer end, the moment of said controlling force varying with said cos 9.

13. The combination with a motor and means for controlling the speed of rotation of said motor, of a governor driven by said motor and havingat least one deflecting weight, a supporting member including a pivotal support; for said weight having its pivotal axis displaced from the axis of rotation thereof by a distance at least eight times its radius as measured from said pivotal axis to the center of gravity of said weight, a control arm secured to said weight at an angle to said radius such that the centrifugal moment through a wide angle of deflection of said weight about said pivotal axis varies as the cosine of the angle of deflection ofsaid weight from a position where said centrifugal moment is a maximum, gravity biasing means for applying to the opposite end of said arm an opposing moment which varies as the cosine of the angle of deflection so that said weight within said wide angle is free to deflect independently of the angular position thereof, and means operable by said weight for operating said control means.

14. In combination, 'a centrifugal governor comprising a deflecting weight rotatable about an axis and movable about a pivotal axis through a wide angle, driving means for rotating said weight about its axis of rotation to develop a centrifugal force tending to deflect said weight about its pivotal axis, a control arm secured to said weight ina flxed angular position, the ratio of the length of the pivotal radius of said weight to the distance between said axes, and the angle between said radius and said control arm, being such that the centrifugal moment of said weight about its pivotal axis is proportional to able by deflection of said weight to control said driving means substantially to maintain said cen-f trifugal moment equal to said biasing moment I irrespective of the position of said weight within said wide angle.

GEORGE R. TOWN.

Certificate of Correction Patent N 0. 2,094,196. September 28, 1937 GEORGE R. TOWN It is hereby certified that errors appear in theprin'ted specification of the above numbered patent requiring correction as follows: Page 2, second column, lines 4647, for v page 4, first column, lines 37 and 40, and page 7, first column, line 59, claim 11, for 9 read ,6; page 5, second column, lines 69 and 73, claim 1, and page 6, first column, lines 18 and 19, claim 2, for 6 read page 7, first column, line 75, claim 12, for comrising readcomprising; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 16th day of November, A. D. 1937.

HENRY VAN ARSDALE, Acting Commissioner of Patents. 

